苔藓植物是许多极端环境下植物演替过程中的先锋植物,研究风沙环境下苔藓植物的分解特征及其对风沙土养分变化的影响对科学评价苔藓结皮层生态功能具有重要意义。采用野外分解试验和室内测定相结合的方法,分析了沙漠苔藓植物残体中元素含量变化及其对风沙土养分含量的影响。结果 表明:在0.41～2.33 a的分解过程中,苔藓植物体全N、全P、全K和全C含量呈现波动降低特征,全Ca含量则总体呈现增加趋势; 苔藓植物体分解拟合方程为Y=115.42e-0.1033x; 苔藓植物残体中N,P,K和C元素平均积累系数分别为0.89,0.93,0.87,0.94,而Ca,Mg和Fe元素的平均积累系数分别为1.05,1.06,1.02。随着沙漠苔藓植物分解过程时间的增加,0—5 cm土层全氮、全磷、速效氮、速效磷和速效钾含量均呈现出不同程度的增加趋势。风沙环境以及苔藓植物N含量较低,其分解过程缓慢,但仍然存在着N,P,K和C元素的释放过程,增加风沙土养分含量。
Bryophytes are pioneers in plant succession in many extreme environments. The study on the decomposition characteristics of desert mossy crust plants and their effects on the changes of nutrients in aeolian sandy soils are important for the scientific evaluation of the ecological functions of moss crusts. The changes of element contents of desert bryophytes and the contents of aeolian sandy soil nutrients were analyzed by the combination of field decomposition test and indoor measurement. The results show that bryophytes decomposition during the period 0.41～2.33 years, the contents of total N, P, K and C of bryophytes present the fluctuating reduction trend, and the content of total Ca increases; the bryophyte decomposition follows the equation, Y=115.42e-0.1033x,and the accumulation coefficients of N, P, K and C in bryophyte residues are 0.89, 0.93, 0.87 and 0.94, respectively, the accumulation coefficients of Ca, Mg and Fe elements are 1.05, 1.06 and 1.02, respectively; the contents of total nitrogen, total phosphorus, available nitrogen, available phosphorus and available potassium in 0—5 cm soil layers show different degrees of increasing trend with the extension of the decomposition process of bryophytes. The decomposition process was slow due to the sandy environment and low N content of desert bryophytes. However, there is still releases of N, P, K and C elements,which increases the nutrient contents of aeolian sandy soil.
